杨其菊201771010134《面向对象程序设计（java）》第六周学习总结

《面向对象程序设计（java）》第六周学习总结

第一部分：理论知识

1）类、超类和子类
2）Object:所有类的超类

3）泛型数组列表
4）对象包装器和自动打包

5）参数数量可变的方法

6）枚举类
7）继承设计的技巧

---

第二部分：实验部分

继承定义与使用《代码测试和示例程序的注释》

1、实验目的与要求

(1) 理解继承的定义；

(2) 掌握子类的定义要求

(3) 掌握多态性的概念及用法；

(4) 掌握抽象类的定义及用途；//不能创建自己的对象，特殊类

(5) 掌握类中4个成员访问权限修饰符的用途；//public和private，

(6) 掌握抽象类的定义方法及用途；

(7)掌握Object类的用途及常用API；//最顶层的类，

(8) 掌握ArrayList类的定义方法及用法；//预定一类

(9) 掌握枚举类定义方法及用途。//预定一类

---

2、实验内容和步骤

实验1： 导入第5章示例程序，测试并进行代码注释。

测试程序1：

•   在elipse IDE中编辑、调试、运行程序5-1 （教材152页-153页） ；

•   掌握子类的定义及用法；

•    结合程序运行结果，理解并总结OO风格程序构造特点，理解Employee和Manager类的关系子类的用途，并在代码中添加注释。

1 package inheritance;
 2
 3 /**
 4  * This program demonstrates inheritance.
 5  * @version 1.21 2004-02-21
 6  * @author Cay Horstmann
 7  */
 8 public class ManagerTest
 9 {
10    public static void main(String[] args)
11    {
12       // 创建一个Manager类对象；
13       Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15);
14       boss.setBonus(5000);
15
16       Employee[] staff = new Employee[3]; //定义一个雇员数组；
17
18       // 用管理者和雇员对象填充数组；
19
20       staff[0] = boss;
21       staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
22       staff[2] = new Employee("Tommy Tester", 40000, 1990, 3, 15);
23
24       // 输出所有雇员对象的信息；
25       for (Employee e : staff)
26          System.out.println("name=" + e.getName() + ",salary=" + e.getSalary());
27
28    }
29 } 

package inheritance;
 2
 3 import java.time.*;
 4
 5 public class Employee
 6 {
 7     //定义Employee属性；
 8    private String name;
 9    private double salary;
10    private LocalDate hireDay;
11    //构造Employee对象，及初始化其属性，
12    public Employee(String name, double salary, int year, int month, int day)
13    {
14       this.name = name;
15       this.salary = salary;
16       hireDay = LocalDate.of(year, month, day);
17    }
18    //name属性访问器
19    public String getName()
20    {
21       return name;
22    }
23    //Salary属性访问器；
24    public double getSalary()
25    {
26       return salary;
27    }
28    //HireDay属性访问器
29    public LocalDate getHireDay()
30    {
31       return hireDay;
32    }
33 //raiseSalary方法；
34    public void raiseSalary(double byPercent)
35    {
36       double raise = salary
37       salary +=raise；
38     } 

1 package inheritance;
 2
 3 public class Manager extends Employee//定义新类Manager是Employee的子类；
 4 {
 5    private double bonus;//子类独有属性；
 6
 7    /**
 8     * @param name the employee's name
 9     * @param salary the salary
10     * @param year the hire year
11     * @param month the hire month
12     * @param day the hire day
13     */
14    //构造Manager对象并初始化其属性；super直接调用父类参数，name,salary, year, month， day，无返回值；
15
16    public Manager(String name, double salary, int year, int month, int day)
17    {
18       super(name, salary, year, month, day);
19       bonus = 0; //Manager独有属性并初始化；
20    }
21    //Salary属性访问器，
22    public double getSalary()
23    {
24        //父类中的方法语句在子类中被重写成“独有方法”；
25       double baseSalary = super.getSalary();
26       return baseSalary + bonus;
27    }
28    //Bonus属性更改器；
29    public void setBonus(double b)
30    {
31       bonus = b;
32    }
33 }

实验结果截图： 

---

测试程序2：

•   编辑、编译、调试运行教材PersonTest程序（教材163页-165页)；

•    掌握超类的定义及其使用要求；

•   掌握利用超类扩展子类的要求；

•    在程序中相关代码处添加新知识的注释。

package abstractClasses;

/**
 * This program demonstrates abstract classes.
 * @version 1.01 2004-02-21
 * @author Cay Horstmann
 */
public class PersonTest
{
   public static void main(String[] args)
   {
      Person[] people = new Person[2];

      // 用学生和雇员对象填充People数组；
      people[0] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
      people[1] = new Student("Maria Morris", "computer science");

      //输出所有Person对象的名称和描述；

for (Person p : people) 
     System.out.println(p.getName() + ", " + p.getDescription());
 }
 }

package abstractClasses;

public abstract class Person  //定义抽象类型Person；

{
 public abstract String getDescription();
 private String name;
 public Person(String name) { 

this.name = name; 
}
//Name属性访问器；
 public String getName() { 

return name; 
}
 }

package abstractClasses;

import java.time.*;

public class Employee extends Person //定义新类Employee是Person的子类
{
//定义属性；

private double salary; 

private LocalDate hireDay;
 public Employee(String name, double salary, int year, int month, int day) { 

  super(name); //调用父类方法；

  this.salary = salary;//this代替当前对象；
   hireDay = LocalDate.of(year, month, day);//LocalDate方法；
 } 
//Salary属性访问器
public double getSalary() 
{ 

return salary;
 } 

public LocalDate getHireDay()
 { 
return hireDay; 
} 
//Description属性访问器，String类型；
public String getDescription() 
{ 

return String.format("an employee with a salary of $%.2f", salary); 
} 
//Employee类独有方法；
public void raiseSalary(double byPercent)
 {
//计算语句；
 double raise = salary * byPercent / 100; salary += raise;
 }
 }

package abstractClasses;

public class Student extends Person//子类Student继承父类Person；
{
   private String major;

   /**
    * @param nama the student's name
    * @param major the student's major
    */
   public Student(String name, String major)
   {
      // 将name传递给父类构造函数；
      super(name);
      this.major = major;
   }

   public String getDescription()
   {
      return "a student majoring in " + major;
   }
}

运行结果如下：

---

测试程序3：

•   编辑、编译、调试运行教材程序5-8、5-9、5-10，结合程序运行结果理解程序（教材174页-177页）；

•  掌握Object类的定义及用法；

•  在程序中相关代码处添加新知识的注释。

package equals;

/**
 * This program demonstrates the equals method.
 * @version 1.12 2012-01-26
 * @author Cay Horstmann
 */
public class EqualsTest
{
   public static void main(String[] args)
   {
      Employee alice1 = new Employee("Alice Adams", 75000, 1987, 12, 15);
      Employee alice2 = alice1;
      Employee alice3 = new Employee("Alice Adams", 75000, 1987, 12, 15);
      Employee bob = new Employee("Bob Brandson", 50000, 1989, 10, 1);

      System.out.println("alice1 == alice2: " + (alice1 == alice2));

      System.out.println("alice1 == alice3: " + (alice1 == alice3));

      System.out.println("alice1.equals(alice3): " + alice1.equals(alice3));

      System.out.println("alice1.equals(bob): " + alice1.equals(bob));

      System.out.println("bob.toString(): " + bob);

      Manager carl = new Manager("Carl Cracker", 80000, 1987, 12, 15);
      Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15);
      boss.setBonus(5000);
      System.out.println("boss.toString(): " + boss);
      System.out.println("carl.equals(boss): " + carl.equals(boss));
      System.out.println("alice1.hashCode(): " + alice1.hashCode());
      System.out.println("alice3.hashCode(): " + alice3.hashCode());
      System.out.println("bob.hashCode(): " + bob.hashCode());
      System.out.println("carl.hashCode(): " + carl.hashCode());
   }
}

package equals;

import java.time.*;
import java.util.Objects;

public class Employee
{
   private String name;
   private double salary;
   private LocalDate hireDay;

   public Employee(String name, double salary, int year, int month, int day)
   {
      this.name = name;
      this.salary = salary;
      hireDay = LocalDate.of(year, month, day);
   }

   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }

   public LocalDate getHireDay()
   {
      return hireDay;
   }

   public void raiseSalary(double byPercent)
   {
      double raise = salary * byPercent / 100;
      salary += raise;
   }

   public boolean equals(Object otherObject)
   {
      //快速检查对象是否相同
      if (this == otherObject) return true;

      //如果显示参数为null,则必须返回false；
      if (otherObject == null) return false;

      // 如果这些 类不匹配，他们不相等。
      if (getClass() != otherObject.getClass()) return false;

      // 现在我们知道另一个对象是非空雇员；
      Employee other = (Employee) otherObject;

      //测试字段是否具有相同的值；
      return Objects.equals(name, other.name) && salary == other.salary && Objects.equals(hireDay, other.hireDay);
   }

   public int hashCode()
   {
      return Objects.hash(name, salary, hireDay);
   }
    //toString方法；
   public String toString()
   {
      return getClass().getName() + "[name=" + name + ",salary=" + salary + ",hireDay=" + hireDay
            + "]";
   }
}

package equals;

public class Manager extends //Employee子类Manager继承父类Employee
{  
  // 定义属性；
   private double bonus;

   public Manager(String name, double salary, int year, int month, int day)
   {
      super(name, salary, year, month, day);//调用父类参数，无返回值；
      bonus = 0;
   }
    //Salary属性访问器；
   public double getSalary()
   {
      double baseSalary = super.getSalary();
      return baseSalary + bonus;
   }

   public void setBonus(double bonus)
   {
      this.bonus = bonus;
   }

   public boolean equals(Object otherObject)
   {
      if (!super.equals(otherObject)) return false;
      Manager other = (Manager) otherObject;
      // 检查这个是否与其他是否属于同一类；
      return bonus == other.bonus;
   }

   public int hashCode()
   {
      return java.util.Objects.hash(super.hashCode(), bonus);
   }

   public String toString()
   {
      return super.toString() + "[bonus=" + bonus + "]";
   }
}

---

测试程序4：

•   在elipse IDE中调试运行程序5-11（教材182页），结合程序运行结果理解程序；

•   掌握ArrayList类的定义及用法；

•    在程序中相关代码处添加新知识的注释。

package arrayList;

import java.util.*;

/**
 * This program demonstrates the ArrayList class.
 * @version 1.11 2012-01-26
 * @author Cay Horstmann
 */
public class ArrayListTest
{
   public static void main(String[] args)
   {
      // 用雇员对象填充staff数组；
      ArrayList<Employee> staff = new ArrayList<>();

      staff.add(new Employee("Carl Cracker", 75000, 1987, 12, 15));
      staff.add(new Employee("Harry Hacker", 50000, 1989, 10, 1));
      staff.add(new Employee("Tony Tester", 40000, 1990, 3, 15));

      //把每个雇员的薪水提高5%；
      for (Employee e : staff)
         e.raiseSalary(5);

      // 打印所有雇员对象的信息；
      for (Employee e : staff)
         System.out.println("name=" + e.getName() + ",salary=" + e.getSalary() + ",hireDay="
               + e.getHireDay());
   }
}

package arrayList;

import java.time.*;

public class Employee
{
   private String name;
   private double salary;
   private LocalDate hireDay;

   public Employee(String name, double salary, int year, int month, int day)
   {
     //注意this的用法;
      this.name = name;
      this.salary = salary;
      hireDay = LocalDate.of(year, month, day);
   }

   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }

   public LocalDate getHireDay()
   {
      return hireDay;
   }

   public void raiseSalary(double byPercent)
   {
      double raise = salary * byPercent / 100;
      salary += raise;
   }
}

---

测试程序5：

•   编辑、编译、调试运行程序5-12（教材189页），结合运行结果理解程序；

•   掌握枚举类的定义及用法；

•    在程序中相关代码处添加新知识的注释。

package enums;

import java.util.*;

/**
 * This program demonstrates enumerated types.
 * @version 1.0 2004-05-24
 * @author Cay Horstmann
 */
public class EnumTest
{
   public static void main(String[] args)
   {

      System.out.print("Enter a size: (SMALL, MEDIUM, LARGE, EXTRA_LARGE) ");
      String input = in.next().toUpperCase();
      Size size = Enum.valueOf(Size.class, input);
      System.out.println("size=" + size);
      System.out.println("abbreviation=" + size.getAbbreviation());
      if (size == Size.EXTRA_LARGE)
         System.out.println("Good job--you paid attention to the _.");
   }
}

enum Size
{
   SMALL("S"), MEDIUM("M"), LARGE("L"), EXTRA_LARGE("XL");

   private Size(String abbreviation) { this.abbreviation = abbreviation; }
   public String getAbbreviation() { return abbreviation; }

   private String abbreviation;
}

---

实验2：编程练习1

•   定义抽象类Shape：

属性：不可变常量double PI，值为3.14；

方法：public double getPerimeter()；public double getArea())。

•   让Rectangle与Circle继承自Shape类。

•   编写double sumAllArea方法输出形状数组中的面积和和double sumAllPerimeter方法输出形状数组中的周长和。

•    main方法中

1）输入整型值n，然后建立n个不同的形状。如果输入rect，则再输入长和宽。如果输入cir，则再输入半径。
2） 然后输出所有的形状的周长之和，面积之和。并将所有的形状信息以样例的格式输出。
3） 最后输出每个形状的类型与父类型，使用类似shape.getClass()(获得类型)，shape.getClass().getSuperclass()(获得父类型);

思考sumAllArea和sumAllPerimeter方法放在哪个类中更合适？

输入样例:

3
rect
1 1
rect
2 2
cir
1

　　

输出样例:

18.28
8.14
[Rectangle [width=1, length=1], Rectangle [width=2, length=2], Circle [radius=1]]
class Rectangle,class Shape
class Rectangle,class Shape
class Circle,class Shape

 package Attention;

 import java.math.*;
 import java.util.*;
 import Attention.Shape;
 import Attention.Rectangle;
 import Attention.Circle;

 public class sum
 {

     public static void main(String[] args)
     {
         Scanner in = new Scanner(System.in);
         String rect = "rect";
         String cir = "cir";
         System.out.print("请输入形状个数:");
         int n = in.nextInt();
         Shape[] score = new Shape[n];
         for(int i=0;i<n;i++)
         {
             System.out.println("请输入形状类型 (rect or cir):");
             String input = in.next();
             if(input.equals(rect))
             {
                 double length = in.nextDouble();
                 double width = in.nextDouble();
                 System.out.println("Rectangle["+"length:"+length+"  width:"+width+"]");
                 score[i] = new Rectangle(width,length);
             }
             if(input.equals(cir))
             {
                 double radius = in.nextDouble();
                 System.out.println("Circle["+"radius:"+radius+"]");
                 score[i] = new Circle(radius);
             }
         }
         Shape c = new Shape();
         System.out.println(c.sumAllPerimeter(score));
         System.out.println(c.sumAllArea(score));
         for(Shape s:score)
         {

             System.out.println(s.getClass()+",  "+s.getClass().getSuperclass());
         }
     }

     public double sumAllArea(Shape core[])
     {
          double sum = 0;
          Object score;
         for(int i = 0;i<score.length;i++)
              sum+= score[i].getArea();
          return sum;
     }

     public double sumAllPerimeter(Shape score[])
     {
          double sum = 0;
          for(int i = 0;i<score.length;i++)
              sum+= score[i].getPerimeter();
          return sum;
     }

 }

 package Attention;

 public abstract class Shape
 {
     double PI = 3.14;//不可变常量double PI，值为3.14；
     //方法：public double getPerimeter()；public double getArea())；
     public abstract double  getPerimeter();
     public abstract double  getArea();
 }

 package Attention;

 public class Rectangle extends Shape  //Rectangle继承自Shape类;
 {
     private double width;
     private double length;
     public Rectangle(double w,double l)
     {
         this.width=w;
         this.length=l;
     }
     public double getPerimeter()
     {
         double Perimeter = (width+length)*2;
         return Perimeter;
     }
     public double getArea()
     {
         double Area = width*length;
         return Area;
     }

       public String toString()
       {
           return getClass().getName() + "[ width=" +  width + "]"+ "[length=" + length + "]";
       }
 }

 package Attention;

 public class Circle extends Shape//Circle继承自Shape类
 {

     private double radius;
     public Circle(double r)
     {
         radius = r;
     }
     public double getPerimeter()
     {
         double Perimeter = 2*PI*radius;
         return Perimeter;
     }
     public double getArea()
     {
         double Area = PI*radius*radius;
         return Area;
     }
     public String toString()
       {
           return  getClass().getName() + "[radius=" + radius + "]";
    }
 }

实验3： 编程练习2

编制一个程序，将身份证号.txt 中的信息读入到内存中，输入一个身份证号或姓名，查询显示查询对象的姓名、身份证号、年龄、性别和出生地。

 package Id;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.util.ArrayList;
 import java.util.Scanner;

 public class ID {

     public static People findPeopleByname(String name) {
         People flag = null;
         for (People people : peoplelist) {
             if(people.getName().equals(name)) {
                 flag = people;
             }
         }
         return flag;

     }

     public static People findPeopleByid(String id) {
         People flag = null;
         for (People people : peoplelist) {
             if(people.getnumber().equals(id)) {
                 flag = people;
             }
         }
         return flag;

     }

     private static ArrayList<People> peoplelist; 

     public static void main(String[] args) {
         peoplelist = new ArrayList<People>();
         Scanner scanner = new Scanner(System.in);
         File file = new File("E:\\面向对象程序设计Java\\实验\\身份证号.txt");
         try {
             FileInputStream files = new FileInputStream(file);
             BufferedReader in = new BufferedReader(new InputStreamReader(files));
             String temp = null;
             while ((temp = in.readLine()) != null) {

                 Scanner linescanner = new Scanner(temp);
                 linescanner.useDelimiter(" ");
                 String name = linescanner.next();
                 String number = linescanner.next();
                 String sex = linescanner.next();
                 String age = linescanner.next();
                 String place = linescanner.nextLine();
                 People people = new People();
                 people.setName(name);
                 people.setnumber(number);
                 people.setage(age);
                 people.setsex(sex);
                 people.setplace(place);
                 peoplelist.add(people);

             }
         } catch (FileNotFoundException e) {
             System.out.println("文件未找到");
             e.printStackTrace();
         } catch (IOException e) {
             System.out.println("文件读取错误");
             e.printStackTrace();
         }
         boolean isTrue = true;
         while (isTrue) {

             System.out.println("***********");
             System.out.println("1.按姓名查询");
             System.out.println("2.按身份证号查询");
             System.out.println("3.退出");
             System.out.println("***********");
             int nextInt = scanner.nextInt();
             switch (nextInt) {
             case 1:
                 System.out.println("请输入姓名:");
                 String peoplename = scanner.next();
                 People person = findPeopleByname(peoplename);
                 if (people != null) {
                     System.out.println("   姓名:"+

person.getName() +  " 身份证号:"+ person.getnumber() +  " 年龄:"+ person.getage()+  " 性别:"+ person.getsex()+  " 地址:"+ person.getplace()   );  } else {  System.out.println("

此人不存在");   }  break;  case 2:  System.out.println("请输入身份证号:");  String peopleid = scanner.next();  People person1 = findPeopleByid(peopleid);  if (people1 != null) {  System.out.println(" 姓名:"+person

1.getName()+  " 身份证号:"+ person1.getnumber()+  " 年龄:"+ person1.getage()+  " 性别:"+ person1.getsex()+  " 地址:"+ person1.getplace());  } else {  System.out.println("此人不存在");   }  break;  case 3:  isTrue = false;  System.out.println("byebye!");  break;  default:  System.out.println("输入有误");   }   }   }    }

 package Id;

 public class Person{

     private    String name;
     private    String number;
     private    String age;
     private    String sex;
     private    String place;

     public String getName()
     {
         return name;
     }
     public void setName(String name)
     {
         this.name = name;
     }
     public String getnumber()
     {
         return number;
     }
     public void setnumber(String number)
     {
         this.number = number;
     }
     public String getage()
     {
         return age;
     }
     public void setage(String age )
     {
         this.age = age;
     }
     public String getsex()
     {
         return sex;
     }
     public void setsex(String sex )
     {
         this.sex = sex;
     }
     public String getplace()
     {
         return place;
     }
     public void setplace(String place)
     {
         this.place = place;
     }
 }

---

第三部分：总结

上周实验课助教老师的详细讲解对我的来说有很大帮助，以及老师在课堂带领我们阅读代码 让我学到很多。总的来说，能力还是很低下，我意识到自己的自主学习能力比较差，这与自身素质方面有很大关系，希望我可以通过这次彻底的认识到自己的问题，提高自己的能力。